This invention relates, in general, to processing within a computing environment, and in particular, to facilitating detection of situations of concern relating to processing within the computing environment.
A commonly encountered error, in computer programs executing within a computing environment, is the use of a memory address formed from a zero-valued register. This is usually considered an error because memory allocated for program use is generally not located at or near location zero. Also, programs generally intend to initialize registers prior to using them in the formation of a memory address, and it is common for the contents of a non-initialized register to be zero.
The detection of this error is difficult, however, and relies upon the detection of some other related error. Memory close to location zero tends to be write-protected to a program, so the mechanism of memory protection will generally alert a program immediately when a store operation is attempted using a zero-valued register. However, in some systems, it is likely that a load operation is legal to a storage address formed with a zero-valued address; the error is only detected if some other check is performed by the program on the validity of the values read from storage.